Oxazolidin-2-one derivatives, preparation method therefor and therapeutical use thereof

A compound of formula (I) in which:

• R.sub.1 represents a hydrogen atom, an alkyl group, a hydroxyalkyl group, a fluoroalkyl group, a hydroxyfluoroalkyl group, a cyanoalkyl group, a phenyl group which is unsubstituted or substituted by a halogen atom or by an alkoxy, nitrile or nitro group, a phenylmethyl group which is unsubstituted or substituted by a halogen atom or by an alkoxy, nitrile or nitro group or an R.sub.3 A- group in which R.sub.3 is a cycloalkyl or cyclooxyalkyl group which is unsubstituted or substituted by a hydroxyl group and A is a --CH.sub.2 or --CH.sub.2 --CH.sub.2 radical,
• R.sub.2 represents a hydrogen atom or a methyl group,
• X represents an oxygen or sulphur atom or an NR.sub.4 group where R.sub.4 is an alkyl group or a hydrogen atom and
• Z represents an oxygen atom or a --CH.dbd.CH or --CH.sub.2 --CH.sub.2 group,
• the said compounds existing in the form of pure enantiomers or diastereoisomers or of a mixture of these different forms.